Daniel van Vugt authored Dec 20, 2018 and Georges Basile Stavracas Neto committed Jun 07, 2019

That could happen if the backend did not provide presentation timestamps,
or if the screen was not changing other than the hardware cursor:

  if (stage_cogl->last_presentation_time == 0||
      stage_cogl->last_presentation_time < now - 150000)
    {
      stage_cogl->update_time = now;
      return;
    }

By setting `update_time` to `now`, master_clock_get_swap_wait_time()
returns 0:

  gint64 now = g_source_get_time (master_clock->source);
  if (min_update_time < now)
    {
      return 0;
    }
  else
    {
      gint64 delay_us = min_update_time - now;
      return (delay_us + 999) / 1000;
    }

However, zero is a value unsupported by the default master clock
due to:

  if (swap_delay != 0)
    return swap_delay;

All cases are now handled by extrapolating when the next presentation
time would be and calculating an appropriate update time to meet that.

We also need to add a check for `update_time == last_update_time`, which
is a situation that just became possible since we support old (or zero)
values of `last_presentation_time`. This avoids getting more than one
stage update per frame interval when input events arrive without
triggering a stage redraw (e.g. moving the hardware cursor).

!363